In recent years various lead systems have been developed specifically designed for implantation in the vasculature of the heart. It is now known that therapeutic stimulation pulses can be delivered to the left side of the heart using a lead advanced through the coronary sinus and great vein of the heart. Such leads can be used as part of a pacing protocol for the treatment of congestive heart failure or to defibrillate the left ventricle.
The path through the vena cava, coronary sinus and great vein is somewhat narrow and includes many turns. As a result, there exists a need for an apparatus which assists the surgeon in advancing the lead along this path.
In the past, various guidewires have been used to position cardiac leads. Also, guide catheters have also been used. See, for example, U.S. Pat. No. 5,775,327 to Randolph et al. However, the apparatus used in the prior art imposed serious size restrictions on the lead, particularly when the lead was to be positioned at or beyond the coronary sinus. The present invention provides an apparatus which simplifies insertion of the lead and allows a larger diameter lead to be used.